Western intelligence sources told Time magazine on Friday that Israel's Mossad is responsible for the latest assassination of an Iranian nuclear scientist.

A magnetic bomb was attached to the door of 32-year-old Mostafa Ahmadi-Roshan's car during the Wednesday morning rush-hour in Tehran. His driver was also killed. Sources tell the magazine Israel was behind three previous assassinations of scientists.

A senior Israeli official told is quoted in the report as saying "yeah, one more… I don't feel sad for him."

On Saturday, Iranian state television said that Iran had evidence the United States was behind the latest assassination. We have reliable documents and evidence that this terrorist act was planned, guided and supported by the CIA," the Iranian foreign ministry said in a letter handed to the Swiss ambassador in Tehran, state TV reported.

"The documents clearly show that this terrorist act was carried out with the direct involvement of CIA-linked agents."